Process of producing ferro-alloys.



, UNITED STATES PATENT OFFICE.

FREDERICK M. BECKET, OF NIAGARA FALLS, NEW YORK, ASSIGNOR TO ELECTRO METAL- LURGICAL COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF WEST VIRGINIA.

PROCESS OF PRODUCING FERN-ALLOYS.

Specification of Letters Patent.

Patented Sept.'8, 1908.

To all whom it may concern: 7

Be it known that I, Fannaarcx M. Bnoxin'r, a subject of the King of England, residing at Niagara Falls, in the county of Ni are and State of New York, have invente certain new and useful Improvements in Processes of Producing Ferro-Alloys, of which the following is a specification.

The object of this invention is to provide a process of producing low-carbon ferroalloys of refractory metals as chromium, tungsten, vanadium and the like by the use of carbide of the alkali earth metals, as calcium carbid or barium carbid, as reduc' ents.

It is well known that calcium carbid possesses strong reducing properties, and that metallic compounds, and more particularly such as contain sulfur, may be reduced b its use. In such case the calcium carbid is usuall employed in such proportion that the c cium sufiices for the reduction, and a part or all of the carbon of the carbid unites with the reduced metal, yieldin therewith either ardefinite carbid or a met '0 product high in carbon. I have discovered that by utilizing the reducing action of calcium carbid or carbids of other alkali earth metals in an electric furnace and under ro er conditions as hereinafter set forth, ot the alkali earth metal and carbon constituents of the carbid may be oxidized with such de es of completeness that the metallic pr not obtained contains less carbon than would be the case if carbon alone were used as a rcduc' agent, the proportion of carbon so used ing sufficient to secure a commercial efliciency of operation.

The process has been found to be particularly applicable to the treatment of the oxid ores or oxidized compounds of the refractory metals chromium, tungsten, and vanadium, which metals as is well known exhibit a strong tendency to combine with free carbon employed as a reducing a cut and to form therewith high carbon pr nets of comparatively low commercial value. As examples of ores which maybe advantageously treated I will specify chromite, chrome iron ore, wolframite, and oxid ores of vanadium or oxid compounds of vanadium produced from its sulfid or other ores. It will be understood that the term ores is employed to include concentrates.

In case silicious ores, or ores yieldi' an acid slag, are treated with calcium car id,

the calcium oxid resulting from the oxida tion of the calcium may be in sufficient proportion to yield with the silica a suitable slag, and in such case no additional flux need be employed; however in case the ores are highly silicious, as for example certain vanadium ores, it will generally be necessary to add additional lime or other basic flux. When on the contrary the process is applied to ores yieldin a basic slag, silica or other acid flux may e added to the charge. In general the charge will be composed to yield a sla ha the proper composition to provide w n mo ten a path for the current; and to impart the heat necessary for the reduction and for the preparation of a prod not of low carbon content.

In practicing the invention the ore, previously crushed or granulated, may be mixed with calcium carbid and with such pro A r- .tions of lime or silica as may be require for the production of a suitable slag. The cha so repared is fed between electro'des, usua 1y 0 carbon or graphite, and is subjected to a tem rature suflicient toproduce a molten bath. Inasmuch as reduction may occur at temperatures less than are required for the substantially complete oxidation of the carbon, such temperatures are provided that the reducing effect of the carbon will be substantially fully utilized,

under which conditions a product low in carbon is obtained. The pro rtions of the components of the charge w' preferably be such that the oxygen of the orewill substantially suffice for the oxidation both of the calcium and the carbon of the carbid.

The articular advantages of the process as applied to the refractory metals mentioned are as follows (1) The metals mentioned possess a high afiinity for free carbon and combine with or absorb the same when carbon is used as areduc' agent; whereas in the use of carbide of alk earth metalsas reducing agents the proportion of carbon in the charge is greaty reduced, and such carbon as is present exists in the combined state, these conditions rendering it far less liable to combine with the meta during the period which must necessarily elapse before all portions of the carbon can exert their reducing'effect upon the ore; (2) the electric furnace operation requires for its efficient practice a comparatively large r0 rtion of slag-forming ingredients, whic it react has been customary to add in the form of lime, silica, etc., proportioned to the requirements of the ore, these materials increasing the Wei ht of the charge for a given output of metal and re uiring the expenditure of a largequantity 0 energy to bring them to a temperature. With oxid ores however ca cium carbid, for'example, as a reducing agent yields calcium oxid, supplying at the same time by the oxidation of calcium a large amount of heat, and to this extent economizing the current in the 0 eration of producing metals and alloys. ile 'electrical energy has been absorbed in the prodoes not occur in sufficient proportion as a constituent of the ore: Ores, as chrome iron ores, containing a considerable proportionof iron do not ordinarily require such addition. Obviously the" oxid ores of iron may be added, but in this case an additional proportion of carbid is required for their reduction.

In all cases the process is preferably ren-v dered continuous by adding fresh portions of the charge as re uired and withdrawing the molten product omtime to time, thereby conserving to the greatest possible degree the-heat of the furnace. I

I claim:

1. The process of producing low-carbon ferroalloyswhich consists in electrically smelting a charge containing a refractory oxid ore, a source of iron and a carbid of an alkali-earth metal, the carbid being present in pro ortion to yield a metallic product low in car on.

2. The process of producing low-carbon ferroalloys which consists in electrically smelting-a charge containing a refracto v oxid ore, a source of iron, a carbid of an a kali-earth metal, and a suitable flux, the carbid being resent in proportion to yield a metallic ro uct low in carbon.

3. he continuous process of producing low-carbon ferroalloys which consists in electrically smelting a charge containin a refractory oxid ore, a source of iron an a carbid of an. alkali-earth metal, the carbid being resent in proportion to yield a metallic pro uct low in carbon, supplying fresh portions ofthe charge as required and withdrawin the product from time to time,

4. T e process of producing low-carbon ferroalloys which consists in electrically smelting a charge containing a refractory oxid ore, a source of iron and calcium carbi the calcium carbid being presentin pro ortion to yield a metallic product low incar on.

5. The process of producing low-carbon ferroalloys which consists in electrically smelting. a charge containing a refractory oxid ore, a source of iron, calcium carbid, and a suitable flux, the calcium carbid being present in pro ortion to yield a metallic product low in car on.

6. The continuous process of producing low-carbon 'ferroalloys which-consists in electrically smelting a charge containing a refrac-' tory oxid ore, a source of iron and calcium carbid, the calcium carbid being present in pro ortion to car on, supp ying fresh ortions of the charge as required and with awing the product from time to time.

7. The process of producing low-carbon 'ferrochrome which consists in electrically smelting a charge containing chrome llOIl ore and calcium carbid, the calcium carbid being present in proportion to yield a metallic prod uct low in carbon.

8. The process of producing low carbon ferrochrome which consists in electrically smelting a charge containin chrome iron ore, calcium carbid, and a suitable flux, the

- calcium carbid being present in proportion to yield a metallic product low in carbon.

9. The continuous process of producing low-carbon ferrochrome which consists in electrically smelting a charge containing chrome iron ore and calcium carbid, the calcium carbid being presentin proportion to yield a metallic product low in carbon, supplying fresh portions of the charge as re-' quired and withdrawing the product from time to time. In testimony whereof, I aflix my signature in presence of two witnesses.

FREDERICK M. BECKET. Witnesses:

J. N. DEINHARDT, DEAN BURGESS.

yield a metallic product low in 

